A. Field of the Invention
The present invention generally relates to temperature control systems and methods, and, more particularly, to a new and improved open-loop self-cleaning oven temperature control system and method.
B. Description of the Prior Art
Self cleaning ovens and temperature controls therefor are old and well known in the prior art as exemplified by U.S. Pat. Nos. 3,121,158; 3,122,626; 3,310,654; 3,327,094; 3,353,004; 3,569,670; 3,648,012; 3,738,174; 3,924,101; 4,166,268; 4,214,224; and 4,369,352. Conventionally, the bake temperature controls for many prior art self-cleaning ovens are capable of being recalibrated in service to compensate for oven components that deviate from design specifications or to accommodate individual user preferences. See, for example, the above-identified '670 patent and the '101 patent and the '352 patent. Some prior art temperature control systems for self-cleaning ovens are designed to maintain a constant clean temperature even though the bake temperatures have been recalibrated and offset by a predetermined amount from nominal values. Recalibration of the bake temperatures in other prior art systems necessarily affect the clean temperature.
With the advent of digital electronic microprocessor based control systems for controlling the temperature in self-cleaning ovens, specific operating characteristics are inherent in a particular design of the control system. For example, in a specific prior art electric range commercially made and sold by the assignee of the present invention, the digital electronic microprocessor based closed-loop control circuit for controlling the temperature of a self-cleaning oven of the range provides a much finer or greater level of temperature control resolution in the BAKE mode than in the CLEAN mode. Therefore, a particular self-cleaning oven that runs too hot or too cool due, for example, to a faulty oven temperature sensor, cannot easily have its clean temperature adjusted during recalibration of the bake temperatures. A need therefore exists to enable the clean temperature of a self-cleaning oven to be adjusted when the bake temperatures of the oven are recalibrated, while limiting the change produced in the clean temperature to a value smaller than that capable of being detected by the closed-loop temperature control system.